Flotation of minerals.



' UNITED STATES PATENT OFFICE.

HARRY'P. OORLISS, OF PITTSBURGH, PENNSYLVANIA, ASSIGN OR TO METALS RECOVERY COMPANY, OF NEW 'YORK, N.', Y., A CORPORATION OF nora'rron or MINERALS.

1,223,184.. No Drawing.

To all whom it may concern: 'Be it known that I, HARRY P. comes, a citizen of the United States, residing at Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements in Flotation of Minerals; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to the concentration of minerals, such as sulfid ores and the like by flotation, and is based upon the discovery that improved results can be obtained by carrying out the flotation operation with the addition to the ore or mineral pulp of nitro-naphthalene, either alone or with added amounts of oil. The nitronaphthalene is a non-oleaginous solid material, which can nevertheless bedistributed throughout the ore pulp with such uniformity that minimum amounts are required' for effecting the concentration of the mineral by flotation. Nitro-naphtha- I lene is obtainable, for example, from naphthalene by treatment with. nitric acid.

Inusingthe ntro-naphthalene it may be added to the ore, either alone or with added amounts of oil in any suitable man-' ner so that it willbe thoroughly and uniformly distributed throughout the ore pulp. The mixture is then subjected to a flotation operation as in an ordinary Gallow cell or in an apparatus where the air is incorporated with the ore pulp by mechanical agitation. With some ore pulps it may be desirable to add either small amounts of acids or of'alkalis depending upon the nature of the ore pulp to be treated.

The amount of nitro-naphthalene'used may vary somewhat, for example between one-half pound and three or four-pounds per tonfof ore (that is, calculated on the weight of the ore and not of the orepulp).

Specification of Letters Patent; Patented May 29, 1917. Application filed. March 21, 1917. Serial as. item. i

The results obtained by carrying on-the flotation with the addition of nitro-naphthalene or with nitro-naphthalene' and added oil indicate that vhigher grades of that recovered from the tailings contains.

notable amounts of nitro-naphthalene which can thus be returned to the process with resulting economy in the amount required to be added for subsequent operations.

In applying the nitr c-naphthalene it may be introduced into the tube mill in which the ore is being ground, or it may be otherwise introduced into the ore pulp in any suitable way, as, for instance, by first digesting it in hot water and mixing the product with the ore pulp just before it enters the flotation cell. 7.

Having thus described my invention,

what I claim is:

1. The method of effecting the concentration of minerals by flotation, which comprises adding to the mineral pulp a small amount of nitro-naphthalene and subjecting the resulting mixture to a flotation operation; substantially as described.

2. The method of efl'ecting the concentration of minerals by flotation, which comprises adding to the mineral pulp a small amount of nitro-naphthalene and of oil and subjecting the resulting'mixture to a flotation operation; substantially as described.

In testimony whereof I aflix my }ignature.

HARRY P. CORLIS S 

